Ali Abdullah Saleh, the outgoing Yemeni president, has formally handed over power to his vice-president, the winner of an uncontested campaign to replace him after 33 years of one-man rule.

During a ceremony in the capital Sanaa on Monday, Saleh congratulated Abd-Rabbu Mansour Hadi, his successor, and said he hoped for a peaceful transition of power.

"All of Yemen's proud citizens are behind him," Saleh said, before handing Hadi a Yemeni flag he called the "banner of the revolution".

"The responsibilities on the shoulders of the new president are immense, but we are confident that with our support he will succeed."

That will not sit well with those who want to see a true transition and other nations that negotiated Saleh's departure, who want him "to understand that from this particular moment he has to completely disappear from the political scene".

'Difficult period'

Saleh called on "international partners" to support Yemen and said the new government must combat terrorism, especially al-Qaeda, which has used months of fighting to increase its foothold.

Hadi said that Yemen faced a "complicated and difficult period" and that the country needed "co-operation" to carry out the terms of a transition deal brokered by Saudi Arabia and other Gulf nations that would see a new president elected in two years.

Saleh, who has steered events in Yemen through his loyalists and extended family and is still seen as controlling the country's affairs, said he would support and stand by Hadi.

Hadi, who took the oath of office on Saturday, received 99 per cent of the 6.6 million votes cast in what was arguably a non-optional referendum, since the only option on the ballots was a "yes" vote for him.

About 25,000 ballots were invalid, the government said.

Monday's ceremony marked the culmination of more than a year of protest and violence aimed at ending Saleh's rule.

What began as street demonstrations in January 2011 in the wake of Tunisia and Egypt's uprisings escalated into urban warfare between government troops and rebel tribes.

Defectors, including a top general, turned against government loyalists, and Saleh himself was seriously injured in an explosion - possibly a mortar blast - at his presidential palace in Sanaa in June.

After backing out many times, Saleh signed a power-transfer deal in November.